(1)若a+b=8,则-(a+b)= _______; (2)若a+b=8,则-a-b=_______;
(3)若x2+y2=1,则-x2-y2_______; (4)若x2+3x+4=0,则x2+3x=_______;
(5)若x2+3x+4=0,则x2+3x-4=_______;(6)若x2+3x+4=0,则2x2+6x-5=_______.
(1)若a+b=8,则-(a+b)= _______; (2)若a+b=8,则-a-b=_______;
(3)若x2+y2=1,则-x2-y2_______; (4)若x2+3x+4=0,则x2+3x=_______;
(5)若x2+3x+4=0,则x2+3x-4=_______;(6)若x2+3x+4=0,则2x2+6x-5=_______.
(1)-8;(2)-8;(3)-1;(4)-4;(5)-8; (6) -13